Undergrate air admission means for lateral feed solid fuel stokers



om. 4, 1949. R :,TOUTON 2,483,946`

UNDEEGRATE AIR AD sIoN MEANS LATERAL FEED so FUEL STOKE Filed March 30, 1944 A v 3 Sheets-Sheel.

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UNDERGRATE AIR ADMISSION MEANS FOR LATERAL FEED SOLID FUEL STOKERS Filed March 5o, 1944 3 sheefs-sheet 2 L T o 'o o l, 0

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Patented Oct. 4, 1949 LATERAL FEED l SOLID FUEL STOKERS vRush D. Tonton, Wynnewood, Pa., assignor to Wurton Machine Company, Philadelphia, Pa., -a corporation of .Pennsylvania Appiimun March 3o, 1944, serial No. 528,657A

This invention relates to a method and apparatus for burning solid fuel, such as, for example, coal, coke, and the like. Y

AMore particularly,'the method and apparatus according to this invention is adaptable for the burning of solid fuel when supplied to a grate by mechanical means, as, for example, a Stoker.

As is well known, when mechanical means, as a Stoker, is used for the supply of fuel for burning, it is customary to feed the fuel to grate means arranged so that the fuel will iiow thereover to form a fuel bed from the point of feed by the Stoker. And it is equally well known to provide air under some pressure beneath the grate means to promote, in cooperation with the stack draft above the fuel bed, the combustion ofthe fuel.

A structure, typical of structures heretofore used, comprises a series of grate bars arranged to extend downwardly from opposite sides of' a hopper into which a stokerfeeds fuel and from which the fuel flows over the grate bars to form a fuel bed. Beneath the grate bars is vformed an air box into: which air is forcedby a blower and from which air passes between the grate bars into the fuel bed to promote combustion of the fuel. Adjacent to the ends of the grate bars, remote from the fuel feed hopper, ash pits are provided into which fall the ashes from the combustion of the fuell it being appreciated that the fuel is fed to the grate bars and travels over the grate bars, the while being consumed by combustion, so that ash is discharged into the ash pit.

In such structure, which is typical in principle and operation to the various structures heretofore known, the fuel bed normally varies in thickness in the extension of the grate bars from the feed hopper to the ash pits, being relatively quite thick adjacent to the feed hopper and being relatively thin adjacent to the ash pits; and such varying thickness is necessary to the flow of the coal'over the'grate bars. In additionto the fact that the fuel bed normally varies in thickness, it is subjected to wide local variation in thickness in its thinner areas due to the removal of clinkers which form' periodically and must* be removed to avoid dead spots in the fuel bed.

\ Due to the variations in normal and: local thickness of the fuel bed, it has been-observed that the air under pressure in the air box, to

which the underside of the whole fuel bed is subjectedequally, tends to pass more rapidly through the thinnest-areas ofl the bed than through the thicker-areas, and to, as it were, tend to blow through thin areas resultant from the re- Claims. (Cl. 110-75) moval of clinker. As a result the combustionof the fuel forming the bed is non-uniform and excessive heat is developed in certain areas, which operates to burn out the grate bars, which must then be replaced at considerable time and expense. y

Now in accordance with this invention, a method and apparatus for burning solidv fuel is provided which will be adaptable to mechanical or Stoker feeding and which will include the provision of means and ysuch mode of operation as to insure uniform combustion throughout the fuel bed and, at the same time, negative the burning out ofthe grate bars.

Having now indicated, in a general way, the nature and purpose of this invention, I will proceed to a detailed description, by way of illustration, of an apparatus, and an embodiment thereof, from a description of `the operation whereof the method will be made apparent, 'all with reference to the accompanying drawings, in which: l

Figure 1 is a sectional view of apparatus according to this invention in combination with a steam generator.

Figure 2 is a cross-sectional View of apparatus embodying this invention.

Figure 3 is a sectional View on line 3 3, Figure 2.

Figure 4 is a cross-sectional view of a modication of the apparatus shown in Figure 2.

Figure 5 is a sectional view on line 5-5, Figure 4.

Referring more particularly to Figures 1-3, A indicates a boiler, of the fire tube type, supported in brick work B, of any usual or desired construction, to provide passage for hot gases beneath the boiler, from a fire box C, over a bridge wall D, through the re tubes of the boiler, over the boiler and to a stack outlet E, as indicated by the arrows, Figure 1.

Extending longitudinally in the re box C is a pair of partition members I, I, provided at their upper ends with flanges 2, `2. The members I, I are spaced from each other and from the side walls of the brick work B and define, with the side walls of the brick work B,`ash pits 3, 3.

Extendingl into the fire box and supported' therein, intermediate the partitions I, I, by the front of the brick work B and the bridge wall Dl is a fuel feed hopper 4,'the edges of which are provided with flanges 5, 5. In the bottom of the hopper is a fuel ram 6, of anyrusual construction, adapted to be moved back and forth in the feed hopper, to feed lfuel thereinto from a supply hopper 1, by any suitably driven mechanism (not shown) contained in casing 8 and connected to the ram 6 by a link 9, a slot I0 being provided in the bottom of the hopper 4 for the passage of the connection I I between the ram and link 9.

It will be appreciated that the ram 6, its driving mechanism andv its connection. therewith comprise-a meohanicalstoker andimawbe ofi any well known construction.

Supported at their ends by the flanges 5, 5 on. feed hopper 4 and the flanges 2, 2, on partition members I, I, are grate bars-swf, I2",- whichA extend: oppositely from the hopper 4 totheashlpit's 3 and, adapted to receive fuel from-fthe hopper. 4,. provide supports for fuel beds ons.oppositefsidesof the hopper. of any usual construction provicng supporting surfaces I2', I2', which slant* dovvnvvardfyf'ronrv The grate bars I2, I2 mosche:-

the edges of the hopper 4 to the edges ofthefashv pits 3, 3, and will be provided with bosses I3 for engagement .witlna shaking deviceindicatedat I4.

Eitending beneath thefinner ends ofthe grate hars I2"I Zlengthwiseof.andladtiacentto .thesides ofthe feed hopper4` are conduits I5, I5, which arerconnectedto a.manifoldl IB, themanifold in t'urn being connected to receive air from a.blower I 'I located o1-1tside-.of` the boiler. front.

' 'Iheconduitsl I5, asfshown. in Figures 2 4and 3, areprovided .withupxlvardlSzl openingV spaced. apertures I8; thespacihg .ofltheapertures, as shown in Fgure', ,d'esinabllr beinggcl'oser. in .the .centralv portion ofi theconduits. than in.` the end portions.A Themanfoldl Il isprovdedwith.. a damper I9 for regulation ofthe flow of.air.from.theblower. tothe conduits, I5, I5 .maybe manually controlled, or., .if Cdesii'ed; ,may hecontrolled .auto- Inaticall'y throughthamediumpf, for example, anywellknownformofelectrical, or,other power, device, indicatedat' 20 under. controlof anywell known suitably, placedheatresponsive element..

The. conduits. I5; I5.A are ,eachprovided with a damper I6"by which the ow of air into thereonduits.. respectively, may be; controlled, for. exampleby.. meansof any. wellknowmelectrical-.device 21, controlled by any well. known. form of heat .responsiveelementaas for. exampl,..a..ther mocouple, suitably pla-ced,..as.,.for; examplebe. tween the inner.. ends ci aspair of the.- grate bars I2, I2. It will be appreciated that, as may bede-V sired, the dampers, |64 may. be controlled. by; a single .device .2.1 or they, may. be4 individually controlledbyproyiding, a .separate control: devicefor each of them.

Referring. now tn .Figures 4- and5, .im addition to..the provision ofthe.. conduits. I.5,.. I5, as `fin .the structure, shown. in Eigures.2 y and 3,. additional conduits 22', 22` and 23,. 23-are..provided .inspaced relationbetween.conduits I.5;,I5 andthewalls. I,

I`; The, several lconduits .areconnected .to.a.maniv fold ,|61 which inturn isfconnectedito.receveair froma blower, as blower I'I Theconduits 2:2, 22 areprovidedavith:upwardly opening apertures J3, .as .in..thecasef, conduits I5? I5,` but are of?. smaller dameterthan the conduits I5`,` I5.. And, likewise,.the,conduits.. 23, 23. are` providedfwith .upwardly opening apertures; I 8. and are ofsmallfer .diameten thanrthefcondu-its. 22, 22. The manifold. IG andthe .severalt conduits will 'be' provided. with dampers,.as Ydescribed .with reference .to ythe structuresshown in Figures 2.and 3; ,andlwhich may7 be .p rovidemwith :heat-respon sive automatic control"devices The. operation. ofi the apparatus according. td thissihventionlas. described aliove .andlwhich.in. volves, the method; according. tov the invention,V

will, it is believed, be apparent. However, assume that a fuel burning bed X is established on the grate bars I2, I2, and that the stoker and blower II are in operation.

By virtue of the operation of the stoker, fuel will be fed into hopper 4, will overflow therefrom onto the grate-bars and,- willfflowl over. the grate bars .towardlthe ash pits 3 Atl-the. same time, air will flow into conduits I5, I5 and streams of air will flow therefrom through apertures I8 and upwardly into the fuel bed between the grate bars.

The `feed*bythe-stolzer will be regulated, in the usualrmanner", so* that the fuel flowing downwarrdluover the grate bars will be consumed on reaching.; their. outer ends, from which the ash will'fallinto'the-ashipits.

Now,` as will be appreciated, the fuel bed will he ofmaxiinum thickness above the feed hopper 4 andiwill gradually thin out toward the outer ends of the grate bars above the ash pits.

kThe. air. stream issuing. from the aperturesfr inconduits I5, ldwlbhenceenter. the fuelbedto supply maximum-,aiuto promotecombustiomadjacent. to .the .thickestcportionrof the; bed; Atthe same time, .theA air. issuing., from. conduits I 5 I5, since it cannot.all.passthroughsthefuel' beddue to its ythicknessfatpthc pointsof. deliveryofthe. air willr create I a. positive.. pressure. inf the. area .surrounding theconduitsor. pressureebox or chamber Y- beneath-the grat'efbars.r vHe1fice.while ain-is diei livered directlyfrom conduits I5., I5.to the/thicker portions. of; the fuel bed; ain under the positive pressure existing in thepressure vbox Y will enter the thinner portion ofthefuelbed.. Y

The .amount of.-.air..supplied toa-the conduits I 5, I5: and discharged through apertures. If. will be controlled by regulation of the dampers I6 andzIa The air.; issuing. fromthe. apertures I8.. in the conduits I5., I 5, it. will .be.noted} exerts-atoooling, effect on :thelinner ends-of. the .grate .barsfand on the. grate shakingmechanism. I4',

The.modifiedtstructures.shown1inA Figures lifand 5 willoperate..asdeScribed abovewith .the provi@ sion.. of additional-streams .o fzair toAk the fuel.bed

" fromthe:conduits-22,12. and; 23023,;v through the apertures. I8,thereinit. being.,.noted that-thc volw urne of airdischargedfromathe conduits 22; 22=`and 2.3,. l2 3 :will-decrease.withdecreasein the.thick-nessv of .the fuel .bed,., since .the fseveralrconduitsereof: dccreaseddiameter, .the-largest:beinggbeneath-the inner. ends-of `the: grate -barse andthe-smallest be'- ing adjacent .theash pit wallsshzI.

By Y virtue of. this.. invention, itt-hase? beenfound that` a: fuel zbedroff, desired; form with -1 highly eilicient combustionicanbemaintainedrwithout the. burning' out-of. grate bars-due-to localr.overheat--V ing; as.hashere-toforerbeen;aficommon occurrencer where, as `in1priorstructures.airfisfsupplied `unlr der. positive .pressure` from'a-r pressure. box tthe fuel. bed. generally; and l consequentlyY passesfinta the fueLbedin greater.. volumef and'henc pro motes ,undesirablyv rapid combustion: in itsrthi-nm ner. as. compared. to.. its: 1 thickerf portions?. or;,. as in. the case of. removal. cfa clinkers; it; were; blows. through. at the poi-nt of..clinl:erremoval:be:-r fore .the. flow of.- fuel. over. the-grate: bar repairs. the bed.

What..I..clain1VJ and.- desire; taprotecm by;r Letter latentds:l i

l. Afurnace for.tb11rningi sol-idfuel comprising; afront wall, a rear wall, andfside. wal1s-:forming a .combustionv.chamber,. a bridge wall extender ing4 acrossfsaid combustionfcha-mber:between the` frontfandlrear walls, there: beingeannain chameber.- betweenftheffurnacefside wallsshaving walls extending from the front wall of the furnace to the bridge wall, a fuel feed hopper between the side walls of the air chamber extending from the front wall of the furnace to the bridge wall forming a portion of the top of the air chamber, grate bars extending laterally from the fuel hopper to the side walls of the air chamber, forming the remainder of the top of the air chamber, means for feeding fuel upwardly out of the hopper and onto the grate bars from the hopper, an air conduit extending longitudinally of the air chamber at each side of the fuel hopper spaced below the grate bars, there being air delivery openings in the upper faces of the conduits for delivering jets of air to the grate bars along the sides of the feed hopper and into the fuel as fed from the hopper, and means for delivering air under pressure to said conduits.

2. A furnace for burning solid fuel, comprising a front wall, a rear wall, and side walls forming a combustion chamber, a bridge wall extending across said combustion chamber between the front and rear walls, there being an air chamber between the furnace side walls extending from the front wall of the furnace to the bridge wall, a fuel feed hopper between the side walls of the air chamber extending from the front wall of the furnace to the bridge wall forming a portion of the top of the air chamber, grate bars eX- tending laterally from the fuel hopper to the side walls of the air chamber forming the remainder of the top of the air chamber, means for feeding fuel upwardly out of the hopper and onto the grate bars from the hopper, a plurality of air conduits extending longitudinally of the air chamber at each side of the fuel hopper spaced below the grate bars, there being air delivery openings in the upper faces of the conduits for delivering jets of air to the grate bars along the sides of the feed hopper, and means for delivering air under pressure to said conduits.

3. A device for burning solid fuel comprising means dening a combustion chamber, a fuel feed hopper of greater length than width extending intosaid combustion chamber, means dening an ash pit in said combustion chamber and parallel to said hopper, grate bars extending laterally from said hopper to said ash pit and arranged to receive fuel from said hopper and for the flow of fuel thereover in a bed of diminishing thickness from the point of receipt of fuel thereon towards the ash pit, means for the supply of fuel to said feed hopper for the maintenance of said fuel bed on said grate bars, means in conjunction with said grate bars dening an air chamber under said grate bars, a conduit in said air chamber having upwardly opening apertures and extending transversely beneath said grate bars lengthwise of and adjacent to said fuel hopper, and means for the supply of air under pressure to said conduit.

4. A device for burning solid fuel comprising means defining a combustion chamber, a fuel feed hopper of greater length than width exjunction with said tending into said combustion chamber, means defining an ash pit in said combustion chamber and parallel to said hopper, grate bars extending laterally from said hopper to said ash pit and arranged to receive fuel from said hopper and for the flow of fuel thereover in a bed of diminishing thickness from the point of receipt of fuel thereon towards the ash pit, means for the supply of fuel to said feed hopper for the maintenance of said fuel bed on said grate bars, means in conjunction with said grate bars defining an air chamber under said grate bars, a conduit in said air chamber having upwardly opening apertures and extending transversely beneath said grate bars lengthwise of and adjacent to said fuel hopper, means for the supply of air under pressure to said conduit, damper means for controlling the admission of air to said conduit, and heat responsive means positioned in said air chamber adjacent to said grate bars for controlling said damper means.

5. A device for burning solid fuel comprising means defining a combustion chamber, a fuel feed hopper of greater length than width extending into said combustion chamber, means delining an ash pit in said combustion chamber and parallel to said hopper, grate bars extending laterally from said hopper to said ash pit and arranged to receive fuel from said hopper and for the flow of fuel thereover in a bed of diminishing thickness from the point of receiptof fuel thereon towards the ash pit, means for the supply of fuel to said feed hopper for the maintenance of said fuel bed on said grate bars, means in congrate bars defining an air chamber under said grate bars, a series of conduits in said air chamber, said onduits having upwardly opening apertures extending in a plane in spaced relation lengthwise of said feed hopper, one of said conduits being adjacent to said feed hopper and the next adjacent conduit being of less diameter than said conduit adjacent to said feed hopper and means for the supply of air un- Y der pressure to said conduits.

RUSH D. TOUTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 205,428 Schultz June 25, 1878 399,688 Moskovits Mar. 19, 1889 510,589 Coxe Dec. 12, 1893 515,612 Richards Feb. 27, 1894 535,413 Richards Mar. 12, 1895 715,569 Franz Dec. 9, 1902 862,730 Graham Aug. 6, 1907 FOREIGN PATENTS Number Country Date 101,560 Australia July 22, 1936 

